German Published Patent Application 34 05 495 describes a device for controlling an internal combustion engine, in which the charge-air pressure is not detected by a sensor, but rather is calculated through a sensor-independent simulation. The simulation specifies the charge-air pressure based upon the rotational frequency and the fuel quantity to be injected.
The periodical article MTZ 50 (1989) 6, p. 263 ff. describes a system for adjusting the exhaust-gas recirculation rate of a pressure-charged diesel engine. The described device provides a lambda probe whose output signal is fed to an automatic control electronic system. The automatic control electronic system then triggers the servomotor of a throttle valve, which influences the exhaust-gas recirculation rate. This signal for triggering the final controlling element depends upon the difference between a lambda setpoint value and a lambda actual value. To compensate for the dead time that occurs in this closed-loop control circuit, a control structure is provided which is very expensive and susceptible to faults.
An object of the present invention is to create the most precise and inexpensive possible controlling system for controlling an internal combustion engine. This objective is solved by the features of the present invention.